Aqa core 3 revision/help???

Thought id make this thread so that anyone who is also going to be revising for C3 over the half term can discuss anything they need help with or just discuss maths in general.

I find C3 harder than C4 personally, particularly the Integration by Substitution questions and the Trig questions.
Missed the lessons on Integration by Substitution and having done some work on it myself I cant seem to get my head around it, I was told its one of the hardest topics on C3 so if anyone can help me out by explaining it to me I would really appreciate that a lot.

Integration by substitution is a nice trick:
$\displaystyle\int f(x) \ dx$ can be reexpressed as:
$\displaystyle\int g(u) \cdot \dfrac{dx}{du} \ du$
Here $g(u)$ is $f(x)$ expressed in terms of $u$ instead of in terms of $x$.

For C3 you'll be told when to do this, and which substitution to use so it's simply a matter of remember that:
$dx=\dfrac{dx}{du} du$ and to replace your x's with u's.
There are most likely plenty of good resources online, I think quite a few like the Examsolutions guy, or there's this which was the top hit on google.

Thank you for that, the link you attached looks like a good place for me to start.